The invention relates to an adjustable front seat arranged in a two-door motor vehicle and having a backrest which has a forward-tilting and an inclination-adjusting movement that takes place about a single axis. Locking of the backrest is brought about by means of a fork latch engaging a catch pin. The locking of the backrest is cancelled by pivoting a spring-loaded detent pawl away from the fork latch.
A backrest which can be pivoted in this general way and which is secured in its position of use is known from German Offenlegungsschrift 2,360,627. This structure gives no guarantee that after a forward-pivoting seat operation, the backrest will be secured once again in its position of use. Non-securing can easily occur when the backrest is not pivoted back completely, or before reaching its rear position, it comes to bear against an obstruction (for example, against a luggage item placed on the rear seats). In the event of a sharp deceleration of the vehicle, an unsecured backrest, which can also be subjected to stress by a passenger sitting behind it, would then exert a load on the back of the seat user. This is especially serious if the backrest receives the upper belt articulation or belt deflection point of a seat belt system.
The object of the instant invention is to effectively prevent the backrest from moving towards the seat user under load, even before the motoring trip begins and even when the backrest cannot return into its secured position of use because of an obstacle.
The invention provides that in an adjustable front seat arranged in a two-door motor vehicle that has a backrest capable of forward-tilting and inclination-adjusting movements about a single axis, locking of the backrest occurs by means of a fork latch engaging with a catch pin and locking is cancelled by the pivoting of a spring-loaded detent pawl away from the fork latch. When a locking position is reached, the detent pawl falls into the fork latch and the detent pawl interacts with a switch member so that when the detent pawl has not fallen in to the fork latch, the switch which, with an associated door closed and an ignition key inserted, activates a backrest-pivoting device to pivot the backrest forwards while the momentary backrest inclination is maintained. Such pivoting of the backrest causes fork latch, which is supported against the catch pin, to pivot about the pin until the detent pawl falls into the fork latch, and the signal is thus stopped.
In seats employed with an integrated belt system it is desirable if there are two backrest-locking mechanisms, located opposite one another at the sides of the seat. Here, when the locking position is reached, each detent pawl falls into its associated fork latch and each detent pawl interacts with its switch member (when the detent pawl has not fallen into its fork latch) to generate a signal which, with the associated door closed and the ignition key inserted, triggers a visual and/or acoustic alarm. When two signals occur as a result of neither detent pawl engaging its respective fork latch, the backrest-pivoting device is activated for effecting pivoting the backrest forwards, while the momentary backrest inclination is maintained, to pivots the fork latches, which are supported against the respective associated catch pins, about their catch pin until at least one of the detent pawls falls into the fork latch. Then one of the signals stops.
Although it is already known from German Offenlegungsschrift 2,926,800 to indicate the incorrect engagement of a backrest-locking device, nevertheless measures for obtaining a secured position of use automatically are not provided.
Since, when two backrest-locking mechanisms are used, it is never possible to ensure completely that both detent pawls fall into their fork latches simultaneously and actuate the associated switch member simultaneously, after one signal has stopped, the fork latches are pivoted further through an additional short predetermined period of time.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.